WASHINGTON - Despite plans for a Defense complex roughly one-sixth the size of the Pentagon, defense contractors in Huntsville could freeze hiring and even begin trimming jobs this summer if Congress doesn't soon resolve its budget battles.

The Pentagon says it isn't planning yet for the deep new spending cuts known as sequestration, which is set to begin in January, but a top congressional staff member said here Tuesday that defense companies can't afford to wait and see what Congress does.

Major defense contractors will begin "shedding" jobs this summer to show Wall Street they have a plan for the $500 billion in additional cuts now set to kick in, according to Robert Simmons, staff director of the House Armed Services Committee.

"We're already seeing deferred hiring," he said. "In the summer, we will see the major defense industry partners shedding jobs. Because they have to prepare themselves."

Simmons was one of a series of leaders and officials briefing a delegation of Huntsville-area business and government leaders on their annual lobbying trip to Washington. The trip is sponsored by the Madison and Morgan county chambers of commerce. Sequestration would be in addition to $487 billion in defense cuts already approved and would mean a total of nearly $1 trillion in defense decreases in the next decade.

Given those numbers, Simmons said another round of BRAC base closings is "dead on arrival in the House" next year and not on the horizon beyond that. BRACs cost big money up front to save money in the long run, he said, and Congress and the Pentagon aren't interested in any new up-front spending.

Nonetheless, current growth continues on the arsenal. U.S. Sen. Richard Shelby, R-Tuscaloosa, told the group the FBI will break ground in June on its new Terrorist Explosive Device Analytical Center on Redstone Arsenal, and September will see the ground-breaking of the fourth building in Redstone Arsenal's Von Braun office complex.

When that complex is complete, Shelby said the Defense Department will have built a complex in Huntsville one-sixth the square footage of the Pentagon. "Don't despair," Shelby said. Huntsville is on the cutting edge of national defense, and defense spending is vital to the nation. "I'm going to do everything I can to fund the initiatives" there, he said.

The sequestration bomb was embedded in the Budget Control Act passed by Congress last year. Unless lawmakers agree to other cuts or revenue increases, the $500 billion in defense budget cuts are automatic.

U.S. Sen. Jeff Sessions, R-Mobile, said he believes a one-year deferral of sequestration will pass Congress late this year. Two plans are floating to do that by adding the revenue to offset what the first year's sequestration would cost.

Huntsville Mayor Tommy Battle agreed Tuesday that cutting defense this deeply just isn't likely. Neither party will want or allow it, Battle said he believes.

But sequestration is the law now, and Simmons said there is "not yet enough inertia to stop the problem." Right now, he said, "there is nothing between us and sequestration."

The chamber group told the representatives such cuts would be "devastating" to the local economy. A 10- percent additional cut in defense spending "directly tracks to reductions in tax revenues affecting schools, roads, public services, housing, etc.," the chamber said in a position paper handed to both senators at a Tuesday breakfast.

Simmons predicted the White House would "hold military personnel benefits exempt" from sequestration, "which pushes the rest of the cut to the Department of Defense to the high side of around 12 percent."

That's the net savings required, Simmons said. Given that most of the DOD's thousands of contracts will require renegotiation or termination liability payments, Simmons said, "When you add it all up ... the actual cost to the Department of Defense to reach 12 percent savings is probably in the 20-percent range.

"My snarky comment to the Air Force is, 'How would you like to renegotiate the tanker contract?' " Simmons said, referring to a bitter fight over new tankers in recent years. "If you think that has our attention, it scares the daylights out of the House Armed Services Committee," Simmons said.